5 Metagenomic data

Species-specific community analyses conducted to generate the data included in these analyses can be found in the annex.

• Amphibians
  • Calotriton asper
  • Lissotriton helveticus
  • Salamandra atra
• Birds
  • Geospizopsis unicolor
  • Perisoreus infaustus
  • Zonotrichia capensis
• Mammals
  • Plecotus auritus
  • Sciurus carolinensis
  • Trichosurus vulpecula
• Reptiles
  • Chalcides striatus
  • Natrix astreptophora
  • Podarcis muralis

5.1 Library complexity

Nonpareil estimate of the metagenomic complexity after removing host DNA.

all_data %>%
    select(dataset,Extraction,nonpareil,Taxon) %>%
    unique() %>%
    group_by(Taxon,Extraction) %>%
    summarise(value = sprintf("%.1f±%.1f", mean(nonpareil), sd(nonpareil))) %>%
    pivot_wider(names_from = Extraction, values_from = value) %>%
    tt(caption = "Mean and standard deviation of breadth of host genome coverage")

Mean and standard deviation of breadth of host genome coverage

Taxon	DREX	EHEX	ZYMO
Amphibian	0.8±0.1	0.8±0.1	0.9±0.1
Bird	1.0±0.0	0.8±0.4	0.9±0.1
Control	0.5±0.6	0.5±0.7	0.0±0.0
Mammal	0.8±0.1	0.7±0.3	0.8±0.2
Reptile	0.9±0.0	0.9±0.1	0.9±0.1

all_data %>%
    select(dataset,Extraction,nonpareil,Taxon) %>%
    unique() %>%
    mutate(Taxon=factor(Taxon,levels=c("Amphibian","Reptile","Mammal","Bird","Control"))) %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    ggplot(aes(x=Extraction,y=nonpareil))+ 
        geom_boxplot() + 
        facet_grid(. ~ Taxon, scales = "free") +
        labs(y="Nonpareil completeness",x="Extraction method")

all_data  %>%
    select(dataset,Extraction,Sample,Species,nonpareil,Taxon) %>%
    unique() %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    filter(Taxon != "Control") %>%
    lmerTest::lmer(nonpareil ~ Extraction + (1 | Sample) + (1 | Species), data = ., REML = FALSE) %>%
    broom.mixed::tidy() %>%
    tt()

effect	group	term	estimate	std.error	statistic	df	p.value
fixed	NA	(Intercept)	0.885552853	0.03450229	25.6664948	40.89542	7.753071e-27
fixed	NA	ExtractionDREX	0.005536892	0.04336611	0.1276779	48.00020	8.989373e-01
fixed	NA	ExtractionEHEX	-0.112193866	0.04336611	-2.5871326	48.00020	1.276294e-02
ran_pars	Sample	sd__(Intercept)	0.059565487	NA	NA	NA	NA
ran_pars	Species	sd__(Intercept)	0.035030813	NA	NA	NA	NA
ran_pars	Residual	sd__Observation	0.150224598	NA	NA	NA	NA

5.2 Alpha diversity

Variance partitioning metrics are derived from community_analysis.Rmd.

alpha_data <- list.files(path = "results", pattern = "^alpha_.*\\.tsv$", full.names = TRUE) %>%
  map_df(~ read_tsv(.)) %>%
  left_join(all_data,by= join_by(dataset==dataset))

alpha_data %>%
    pivot_longer(!c(dataset,Library,Species,Taxon,Sample,Extraction), names_to = "metric", values_to = "value") %>%
    mutate(metric=factor(metric,levels=c("richness","neutral","phylogenetic"))) %>%
    mutate(Taxon=factor(Taxon,levels=c("Amphibian","Reptile","Mammal"))) %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    ggplot(aes(x=Extraction,y=value))+ 
        geom_boxplot() + 
        facet_grid(metric ~ Taxon, scales = "free")

5.2.1 Richness

alpha_data %>%
    select(dataset,Extraction,Sample,Species,richness,Taxon) %>%
    unique() %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    lmerTest::lmer(richness ~ Extraction + (1 | Sample) + (1 | Species), data = ., REML = FALSE) %>%
    broom.mixed::tidy() %>%
    tt()

effect	group	term	estimate	std.error	statistic	df	p.value
fixed	NA	(Intercept)	59.44444444	10.715517	5.5475108	10.12322	0.000234351
fixed	NA	ExtractionDREX	0.05555556	4.453352	0.0124750	34.97883	0.990117532
fixed	NA	ExtractionEHEX	1.38257472	4.545332	0.3041746	35.13134	0.762789322
ran_pars	Sample	sd__(Intercept)	16.00359332	NA	NA	NA	NA
ran_pars	Species	sd__(Intercept)	28.56742258	NA	NA	NA	NA
ran_pars	Residual	sd__Observation	13.36005511	NA	NA	NA	NA

5.2.2 Neutral

alpha_data %>%
    select(dataset,Extraction,Sample,Species,neutral,Taxon) %>%
    unique() %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    lmerTest::lmer(neutral ~ Extraction + (1 | Sample) + (1 | Species), data = ., REML = FALSE) %>%
    broom.mixed::tidy() %>%
    tt()

effect	group	term	estimate	std.error	statistic	df	p.value
fixed	NA	(Intercept)	29.5413181	5.139162	5.7482754	9.895197	0.000193227
fixed	NA	ExtractionDREX	-2.1102758	1.922343	-1.0977625	35.042971	0.279794105
fixed	NA	ExtractionEHEX	-0.3422373	1.962694	-0.1743712	35.152526	0.862574163
ran_pars	Sample	sd__(Intercept)	8.6429526	NA	NA	NA	NA
ran_pars	Species	sd__(Intercept)	13.5543072	NA	NA	NA	NA
ran_pars	Residual	sd__Observation	5.7670282	NA	NA	NA	NA

5.2.3 Phylogenetic

alpha_data %>%
    select(dataset,Extraction,Sample,Species,phylogenetic,Taxon) %>%
    unique() %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    lmerTest::lmer(phylogenetic ~ Extraction + (1 | Sample) + (1 | Species), data = ., REML = FALSE) %>%
    broom.mixed::tidy() %>%
    tt()

effect	group	term	estimate	std.error	statistic	df	p.value
fixed	NA	(Intercept)	4.7721984	0.4324985	11.034024	9.653749	8.685116e-07
fixed	NA	ExtractionDREX	0.1521100	0.1403528	1.083769	35.015284	2.858737e-01
fixed	NA	ExtractionEHEX	0.1852709	0.1433723	1.292236	35.056809	2.047290e-01
ran_pars	Sample	sd__(Intercept)	1.2179889	NA	NA	NA	NA
ran_pars	Species	sd__(Intercept)	0.9236345	NA	NA	NA	NA
ran_pars	Residual	sd__Observation	0.4210584	NA	NA	NA	NA

5.3 Microbial complexity recovery

all_data %>%
    select(dataset,Extraction,microbial_fraction,MAG_mapping_percentage,Taxon) %>%
    mutate(damr=pmin(1,MAG_mapping_percentage/(microbial_fraction*100))) %>%
    mutate(damr=ifelse(is.na(damr),0,damr)) %>%
    unique() %>%
    group_by(Taxon,Extraction) %>%
    summarise(value = sprintf("%.1f±%.1f", mean(damr), sd(damr))) %>%
    pivot_wider(names_from = Extraction, values_from = value) %>%
    tt(caption = "Mean and standard deviation of breadth of host genome coverage")

Mean and standard deviation of breadth of host genome coverage

Taxon	DREX	EHEX	ZYMO
Amphibian	0.8±0.3	0.8±0.3	0.8±0.4
Bird	0.5±0.4	0.6±0.4	0.6±0.4
Control	1.0±0.0	1.0±0.0	1.0±0.0
Mammal	0.9±0.1	0.8±0.3	0.8±0.1
Reptile	1.0±0.0	1.0±0.0	0.9±0.1

all_data %>%
    select(dataset,Extraction,microbial_fraction,MAG_mapping_percentage,Taxon) %>%
    mutate(damr=pmin(1,MAG_mapping_percentage/(microbial_fraction*100))) %>%
    mutate(damr=ifelse(is.na(damr),0,damr)) %>%
    unique() %>%
    mutate(Taxon=factor(Taxon,levels=c("Amphibian","Reptile","Mammal","Bird","Control"))) %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    ggplot(aes(x=Extraction,y=damr))+ 
        geom_boxplot() + 
        facet_grid(. ~ Taxon, scales = "free") +
        labs(y="Domain-adjusted mapping rate",x="Extraction method")

all_data  %>%
    select(dataset,Extraction,microbial_fraction,MAG_mapping_percentage,Taxon, Sample, Species) %>%
    mutate(damr=pmin(1,MAG_mapping_percentage/(microbial_fraction*100))) %>%
    mutate(damr=ifelse(is.na(damr),0,damr)) %>%
    unique() %>%
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    filter(Taxon != "Control") %>%
    lmerTest::lmer(damr ~ Extraction + (1 | Sample) + (1 | Species), data = ., REML = FALSE) %>%
    broom.mixed::tidy() %>%
    tt()

effect	group	term	estimate	std.error	statistic	df	p.value
fixed	NA	(Intercept)	0.78271978	0.06660971	11.7508366	15.45687	4.117676e-09
fixed	NA	ExtractionDREX	0.03348421	0.03977983	0.8417385	130.19072	4.014779e-01
fixed	NA	ExtractionEHEX	0.02228400	0.03999367	0.5571881	130.24817	5.783552e-01
ran_pars	Sample	sd__(Intercept)	0.12024342	NA	NA	NA	NA
ran_pars	Species	sd__(Intercept)	0.19047224	NA	NA	NA	NA
ran_pars	Residual	sd__Observation	0.20283813	NA	NA	NA	NA

5.4 Variance partitioning

Variance partitioning metrics are derived from community_analysis.Rmd.

variance_data <- list.files(path = "results", pattern = "^var_.*\\.tsv$", full.names = TRUE) %>%
  map_df(~ read_tsv(.))

variance_data %>% summarise(mean=mean(r2),sd=sd(r2))

# A tibble: 1 × 2
   mean     sd
  <dbl>  <dbl>
1 0.102 0.0768

variance_data %>%
    left_join(sample_metadata %>% select(Species,Taxon) %>% unique(),by=join_by(species==Species)) %>%
    mutate(metric=factor(metric,levels=c("richness","neutral","phylogenetic"))) %>%
    mutate(Taxon=factor(Taxon,levels=c("Amphibian","Reptile","Mammal"))) %>%
    ggplot(aes(x=Taxon,y=r2)) +
    geom_boxplot()+
    ylim(0,1)+
    facet_grid(. ~ metric, scales = "free")

variance_data %>%
    group_by(metric) %>%
    summarise(mean=mean(r2),sd=sd(r2)) %>%
    tt()

metric	mean	sd
neutral	0.06201935	0.04744380
phylogenetic	0.07381277	0.06884687
richness	0.16970818	0.06626388

5.5 Combined community analysis

species="combined"
genus=species

sample_metadata <- read_tsv(paste0("data/metadata.tsv")) %>%
    rename(dataset=Dataset)

read_counts <- read_tsv("https://sid.erda.dk/share_redirect/BaMZodj9sA/DMB/DMB0134/DMB0134_counts.tsv.gz") %>%
  rename(genome = 1)

genome_metadata <- read_tsv("https://sid.erda.dk/share_redirect/BaMZodj9sA/DMB/DMB0134/DMB0134_mag_info.tsv.gz") %>%
  rename(genome = 1, length=mag_size)

genome_coverage <- read_tsv("https://sid.erda.dk/share_redirect/BaMZodj9sA/DMB/DMB0134/DMB0134_coverage.tsv.gz") %>%
  rename(genome = 1)

download.file("https://sid.erda.dk/share_redirect/BaMZodj9sA/DMB/DMB0134/DMB0134.tree.gz", "data/DMB0134.tree.gz")
genome_tree <- read_tree("data/DMB0134.tree.gz")

5.5.1 Filter data

#Filter by coverage
min_coverage=0.3
read_counts_filt <- genome_coverage %>%
  mutate(across(where(is.numeric), ~ ifelse(. > min_coverage, 1, 0))) %>%
  mutate(across(-1, ~ . * read_counts[[cur_column()]]))

# Transform  to genome counts (non-filtered)
readlength=150
genome_counts <- read_counts %>%
  mutate(across(where(is.numeric), ~ . / (genome_metadata$length / readlength) ))

# Transform to genome counts (coverage-filtered)
readlength=150
genome_counts_filt <- read_counts_filt %>%
  mutate(across(where(is.numeric), ~ . / (genome_metadata$length / readlength) ))

5.5.2 Community barplot

# Retrieve EHI taxonomy colors
phylum_colors <- read_tsv("https://raw.githubusercontent.com/earthhologenome/EHI_taxonomy_colour/main/ehi_phylum_colors.tsv") %>%
  right_join(genome_metadata, by=join_by(phylum == phylum)) %>%
    select(phylum, colors) %>%
    unique() %>%
    arrange(phylum) %>%
    select(colors) %>%
    pull()

# Stacked barplot
genome_counts_filt %>%
    mutate_at(vars(-genome), funs(./sum(., na.rm = TRUE)))  %>% #apply TSS nornalisation
    pivot_longer(-genome, names_to = "dataset", values_to = "count") %>%
    left_join(., genome_metadata, by = join_by(genome == genome)) %>% #append taxonomy
    left_join(., sample_metadata, by = join_by(dataset == dataset)) %>% #append taxonomy
    mutate(Extraction=factor(Extraction,levels=c("ZYMO","DREX","EHEX"))) %>%
    filter(Taxon != "Control") %>%
    ggplot(., aes(x=dataset,y=count,fill=phylum, group=phylum))+ #grouping enables keeping the same sorting of taxonomic units
          geom_bar(stat="identity", colour="white", linewidth=0.1)+ #plot stacked bars with white borders
          scale_fill_manual(values=phylum_colors) +
          labs(y = "Relative abundance") +
          facet_nested(. ~ Taxon + Species + Sample + Extraction, scales="free_x") +
          guides(fill = guide_legend(ncol = 3)) +
          theme(axis.text.x = element_text(angle = 90, vjust = 0.5, hjust=1),
                          axis.title.x = element_blank(),
                panel.background = element_blank(),
                panel.border = element_blank(),
                panel.grid.major = element_blank(),
                panel.grid.minor = element_blank(),
                axis.line = element_line(linewidth = 0.5, linetype = "solid", colour = "black"),
                legend.position="none",
                legend.title=element_blank(),
                panel.spacing = unit(0, "lines"))

ggsave(paste0("figures/barplot_",genus,".pdf"))

genome_counts_NMDS <- genome_counts_filt %>%
            column_to_rownames(var="genome") %>%
            select(where(~!all(. == 0))) %>%
            hillpair(.,q=1, metric="C", out="dist") %>%
            metaMDS(.,trymax = 999, k=2, trace=0) %>%
            vegan::scores() %>%
            as_tibble(., rownames = "dataset") %>%
            left_join(sample_metadata, by = join_by(dataset == dataset)) %>%
            filter(Taxon != "Control") %>%
            group_by(Sample) %>%
            mutate(sample_x=mean(NMDS1), sample_y=mean(NMDS2))

genome_counts_NMDS %>%
            ggplot(., aes(x=NMDS1,y=NMDS2, color=Species, shape=Extraction)) +
                scale_color_manual(values=c("#92d4d1","#9cba7b","#d9d88d","#40bfb8","#73a842","#c2c935","#bf7777","#4a7135","#25968e","#aa3333","#5e1717","#8d8e35")) +
                geom_point(size=3, alpha=0.8) +
                geom_segment(aes(x=sample_x, y=sample_y, xend=NMDS1, yend=NMDS2), alpha=0.2) +
                theme_classic() +
                theme(legend.position="right", legend.box="vertical") +
                guides(color=guide_legend(title="Species"))